Hardships of childhood, access to education quality and social networks, exposure to violence, and many other social domains may slowly accumulate over time and decades later may shape how the brain growth, connects, and copes. In a new ground-breaking work published in Nature Communications, researchers found that an adverse social exposome — cumulative exposure to factors such as low education, adverse childhood experiences, food insecurity, financial stress, low access to healthcare, and traumatic events — is linked to poorer cognition and mental health, reduced functional ability, and alterations in brain structure and function.
These effects have long-lasting impacts not only in healthy ageing, but also in people living with dementia. This work suggests that healthy ageing dementia prevention should begin in childhood and was conducted by an international team of researchers from the Global Brain Health Institute at Trinity College Dublin, the Multipartner Consortium to expand dementia research in Latin America, and the Latin American Brain Health Institute.
The researchers first created and validated an assessment of social exposome assessing 319 dimensions for education, food insecurity, financial status, assets, healthcare access, childhood labour, subjective and objective socioeconomic status, childhood experiences, traumatic events, and relationships. These scores were evaluated in 2,211 individuals (controls, Alzheimer’s disease, and frontotemporal lobar degeneration) from six Latin American countries.
In brief, the more adverse the social exposome, the larger the cognitive, functional, mental and brain impairments. Diverse social and environmental factors at different stages of life were associated with multiple dimensions of brain health. Adverse exposomes were associated with poorer cognition in healthy ageing.
In dementia, more complex exposomes (food insecurity, financial status, socioeconomic status, and access to healthcare) correlated with lower cognitive and functional performance, higher mental health symptoms, and brain structure and connectivity. More importantly, the accumulation of these exposures across the lifespan, rather than the impact of individual components assessed in isolation, showed the strongest associations.
The variations in participants’ country of origin, demographic and dementia- related factors, image acquisition methods, or signal quality did not account for the results. Together, findings highlight how compounded social adversity becomes biologically embedded in brain structure and function. The tailored modelling of social exposome capture precise brain health outcomes of ageing and dementia.
Dr Joaquín Migeot, neuroscientist, Atlantic Fellow at the Global Brain Health Institute (GBHI) at Trinity College and first author, said: “The interaction between modifiable risk factors and the social exposome offers a path toward developing precision dementia prevention agendas tailored to each individual’s social exposome and risk profile.”
Prof Agustin Ibanez, Professor in Brain Health at the Global Brain Health Institute at Trinity, and School of Medicine, Trinity, and Director of the Latin American Brain health Institute (BrainLat), Universidad Adolfo ibanez, lead and corresponding author, added: “[This is] A systematic association of the multidimensional social lifespan experiences on brain health outcomes. These results call for the development of tailored models incorporating the impact of lifespan social environments in the biological embedding of ageing and dementia.”
